diff --git a/abci/client/client.go b/abci/client/client.go
index dd19425c9..5940a7900 100644
--- a/abci/client/client.go
+++ b/abci/client/client.go
@@ -30,10 +30,6 @@ type Client interface {
 
 	Error() error
 
-	// Asynchronous requests
-	CheckTxAsync(context.Context, types.RequestCheckTx) (*ReqRes, error)
-
-	// Synchronous requests
 	Flush(context.Context) error
 	Echo(ctx context.Context, msg string) (*types.ResponseEcho, error)
 	Info(context.Context, types.RequestInfo) (*types.ResponseInfo, error)
diff --git a/abci/client/grpc_client.go b/abci/client/grpc_client.go
index ec9471fd8..0f2eb5ade 100644
--- a/abci/client/grpc_client.go
+++ b/abci/client/grpc_client.go
@@ -164,179 +164,64 @@ func (cli *grpcClient) Error() error {
 
 //----------------------------------------
 
-// NOTE: call is synchronous, use ctx to break early if needed
-// NOTE: call is synchronous, use ctx to break early if needed
-func (cli *grpcClient) CheckTxAsync(ctx context.Context, params types.RequestCheckTx) (*ReqRes, error) {
-	req := types.ToRequestCheckTx(params)
-	res, err := cli.client.CheckTx(ctx, req.GetCheckTx(), grpc.WaitForReady(true))
-	if err != nil {
-		return nil, err
-	}
-	return cli.finishAsyncCall(ctx, req, &types.Response{Value: &types.Response_CheckTx{CheckTx: res}})
-}
-
-// finishAsyncCall creates a ReqRes for an async call, and immediately populates it
-// with the response. We don't complete it until it's been ordered via the channel.
-func (cli *grpcClient) finishAsyncCall(ctx context.Context, req *types.Request, res *types.Response) (*ReqRes, error) {
-	reqres := NewReqRes(req)
-	reqres.Response = res
-	select {
-	case cli.chReqRes <- reqres: // use channel for async responses, since they must be ordered
-		return reqres, nil
-	case <-ctx.Done():
-		return nil, ctx.Err()
-	}
-}
-
-// finishSyncCall waits for an async call to complete. It is necessary to call all
-// sync calls asynchronously as well, to maintain call and response ordering via
-// the channel, and this method will wait until the async call completes.
-func (cli *grpcClient) finishSyncCall(reqres *ReqRes) *types.Response {
-	// It's possible that the callback is called twice, since the callback can
-	// be called immediately on SetCallback() in addition to after it has been
-	// set. This is because completing the ReqRes happens in a separate critical
-	// section from the one where the callback is called: there is a race where
-	// SetCallback() is called between completing the ReqRes and dispatching the
-	// callback.
-	//
-	// We also buffer the channel with 1 response, since SetCallback() will be
-	// called synchronously if the reqres is already completed, in which case
-	// it will block on sending to the channel since it hasn't gotten around to
-	// receiving from it yet.
-	//
-	// ReqRes should really handle callback dispatch internally, to guarantee
-	// that it's only called once and avoid the above race conditions.
-	var once sync.Once
-	ch := make(chan *types.Response, 1)
-	reqres.SetCallback(func(res *types.Response) {
-		once.Do(func() {
-			ch <- res
-		})
-	})
-	return <-ch
-}
-
-//----------------------------------------
-
 func (cli *grpcClient) Flush(ctx context.Context) error { return nil }
 
 func (cli *grpcClient) Echo(ctx context.Context, msg string) (*types.ResponseEcho, error) {
-	req := types.ToRequestEcho(msg)
-	return cli.client.Echo(ctx, req.GetEcho(), grpc.WaitForReady(true))
+	return cli.client.Echo(ctx, types.ToRequestEcho(msg).GetEcho(), grpc.WaitForReady(true))
 }
 
-func (cli *grpcClient) Info(
-	ctx context.Context,
-	params types.RequestInfo,
-) (*types.ResponseInfo, error) {
-	req := types.ToRequestInfo(params)
-	return cli.client.Info(ctx, req.GetInfo(), grpc.WaitForReady(true))
+func (cli *grpcClient) Info(ctx context.Context, params types.RequestInfo) (*types.ResponseInfo, error) {
+	return cli.client.Info(ctx, types.ToRequestInfo(params).GetInfo(), grpc.WaitForReady(true))
 }
 
-func (cli *grpcClient) CheckTx(
-	ctx context.Context,
-	params types.RequestCheckTx,
-) (*types.ResponseCheckTx, error) {
-
-	reqres, err := cli.CheckTxAsync(ctx, params)
-	if err != nil {
-		return nil, err
-	}
-	return cli.finishSyncCall(reqres).GetCheckTx(), cli.Error()
+func (cli *grpcClient) CheckTx(ctx context.Context, params types.RequestCheckTx) (*types.ResponseCheckTx, error) {
+	return cli.client.CheckTx(ctx, types.ToRequestCheckTx(params).GetCheckTx(), grpc.WaitForReady(true))
 }
 
-func (cli *grpcClient) Query(
-	ctx context.Context,
-	params types.RequestQuery,
-) (*types.ResponseQuery, error) {
-	req := types.ToRequestQuery(params)
-	return cli.client.Query(ctx, req.GetQuery(), grpc.WaitForReady(true))
+func (cli *grpcClient) Query(ctx context.Context, params types.RequestQuery) (*types.ResponseQuery, error) {
+	return cli.client.Query(ctx, types.ToRequestQuery(params).GetQuery(), grpc.WaitForReady(true))
 }
 
 func (cli *grpcClient) Commit(ctx context.Context) (*types.ResponseCommit, error) {
-	req := types.ToRequestCommit()
-	return cli.client.Commit(ctx, req.GetCommit(), grpc.WaitForReady(true))
+	return cli.client.Commit(ctx, types.ToRequestCommit().GetCommit(), grpc.WaitForReady(true))
 }
 
-func (cli *grpcClient) InitChain(
-	ctx context.Context,
-	params types.RequestInitChain,
-) (*types.ResponseInitChain, error) {
-
-	req := types.ToRequestInitChain(params)
-	return cli.client.InitChain(ctx, req.GetInitChain(), grpc.WaitForReady(true))
+func (cli *grpcClient) InitChain(ctx context.Context, params types.RequestInitChain) (*types.ResponseInitChain, error) {
+	return cli.client.InitChain(ctx, types.ToRequestInitChain(params).GetInitChain(), grpc.WaitForReady(true))
 }
 
-func (cli *grpcClient) ListSnapshots(
-	ctx context.Context,
-	params types.RequestListSnapshots,
-) (*types.ResponseListSnapshots, error) {
-
-	req := types.ToRequestListSnapshots(params)
-	return cli.client.ListSnapshots(ctx, req.GetListSnapshots(), grpc.WaitForReady(true))
+func (cli *grpcClient) ListSnapshots(ctx context.Context, params types.RequestListSnapshots) (*types.ResponseListSnapshots, error) {
+	return cli.client.ListSnapshots(ctx, types.ToRequestListSnapshots(params).GetListSnapshots(), grpc.WaitForReady(true))
 }
 
-func (cli *grpcClient) OfferSnapshot(
-	ctx context.Context,
-	params types.RequestOfferSnapshot,
-) (*types.ResponseOfferSnapshot, error) {
-
-	req := types.ToRequestOfferSnapshot(params)
-	return cli.client.OfferSnapshot(ctx, req.GetOfferSnapshot(), grpc.WaitForReady(true))
+func (cli *grpcClient) OfferSnapshot(ctx context.Context, params types.RequestOfferSnapshot) (*types.ResponseOfferSnapshot, error) {
+	return cli.client.OfferSnapshot(ctx, types.ToRequestOfferSnapshot(params).GetOfferSnapshot(), grpc.WaitForReady(true))
 }
 
-func (cli *grpcClient) LoadSnapshotChunk(
-	ctx context.Context,
-	params types.RequestLoadSnapshotChunk) (*types.ResponseLoadSnapshotChunk, error) {
-
-	req := types.ToRequestLoadSnapshotChunk(params)
-	return cli.client.LoadSnapshotChunk(ctx, req.GetLoadSnapshotChunk(), grpc.WaitForReady(true))
+func (cli *grpcClient) LoadSnapshotChunk(ctx context.Context, params types.RequestLoadSnapshotChunk) (*types.ResponseLoadSnapshotChunk, error) {
+	return cli.client.LoadSnapshotChunk(ctx, types.ToRequestLoadSnapshotChunk(params).GetLoadSnapshotChunk(), grpc.WaitForReady(true))
 }
 
-func (cli *grpcClient) ApplySnapshotChunk(
-	ctx context.Context,
-	params types.RequestApplySnapshotChunk) (*types.ResponseApplySnapshotChunk, error) {
-
-	req := types.ToRequestApplySnapshotChunk(params)
-	return cli.client.ApplySnapshotChunk(ctx, req.GetApplySnapshotChunk(), grpc.WaitForReady(true))
+func (cli *grpcClient) ApplySnapshotChunk(ctx context.Context, params types.RequestApplySnapshotChunk) (*types.ResponseApplySnapshotChunk, error) {
+	return cli.client.ApplySnapshotChunk(ctx, types.ToRequestApplySnapshotChunk(params).GetApplySnapshotChunk(), grpc.WaitForReady(true))
 }
 
-func (cli *grpcClient) PrepareProposal(
-	ctx context.Context,
-	params types.RequestPrepareProposal) (*types.ResponsePrepareProposal, error) {
-
-	req := types.ToRequestPrepareProposal(params)
-	return cli.client.PrepareProposal(ctx, req.GetPrepareProposal(), grpc.WaitForReady(true))
+func (cli *grpcClient) PrepareProposal(ctx context.Context, params types.RequestPrepareProposal) (*types.ResponsePrepareProposal, error) {
+	return cli.client.PrepareProposal(ctx, types.ToRequestPrepareProposal(params).GetPrepareProposal(), grpc.WaitForReady(true))
 }
 
-func (cli *grpcClient) ProcessProposal(
-	ctx context.Context,
-	params types.RequestProcessProposal) (*types.ResponseProcessProposal, error) {
-
-	req := types.ToRequestProcessProposal(params)
-	return cli.client.ProcessProposal(ctx, req.GetProcessProposal(), grpc.WaitForReady(true))
+func (cli *grpcClient) ProcessProposal(ctx context.Context, params types.RequestProcessProposal) (*types.ResponseProcessProposal, error) {
+	return cli.client.ProcessProposal(ctx, types.ToRequestProcessProposal(params).GetProcessProposal(), grpc.WaitForReady(true))
 }
 
-func (cli *grpcClient) ExtendVote(
-	ctx context.Context,
-	params types.RequestExtendVote) (*types.ResponseExtendVote, error) {
-
-	req := types.ToRequestExtendVote(params)
-	return cli.client.ExtendVote(ctx, req.GetExtendVote(), grpc.WaitForReady(true))
+func (cli *grpcClient) ExtendVote(ctx context.Context, params types.RequestExtendVote) (*types.ResponseExtendVote, error) {
+	return cli.client.ExtendVote(ctx, types.ToRequestExtendVote(params).GetExtendVote(), grpc.WaitForReady(true))
 }
 
-func (cli *grpcClient) VerifyVoteExtension(
-	ctx context.Context,
-	params types.RequestVerifyVoteExtension) (*types.ResponseVerifyVoteExtension, error) {
-
-	req := types.ToRequestVerifyVoteExtension(params)
-	return cli.client.VerifyVoteExtension(ctx, req.GetVerifyVoteExtension(), grpc.WaitForReady(true))
+func (cli *grpcClient) VerifyVoteExtension(ctx context.Context, params types.RequestVerifyVoteExtension) (*types.ResponseVerifyVoteExtension, error) {
+	return cli.client.VerifyVoteExtension(ctx, types.ToRequestVerifyVoteExtension(params).GetVerifyVoteExtension(), grpc.WaitForReady(true))
 }
 
-func (cli *grpcClient) FinalizeBlock(
-	ctx context.Context,
-	params types.RequestFinalizeBlock) (*types.ResponseFinalizeBlock, error) {
-
-	req := types.ToRequestFinalizeBlock(params)
-	return cli.client.FinalizeBlock(ctx, req.GetFinalizeBlock(), grpc.WaitForReady(true))
+func (cli *grpcClient) FinalizeBlock(ctx context.Context, params types.RequestFinalizeBlock) (*types.ResponseFinalizeBlock, error) {
+	return cli.client.FinalizeBlock(ctx, types.ToRequestFinalizeBlock(params).GetFinalizeBlock(), grpc.WaitForReady(true))
 }
diff --git a/abci/client/local_client.go b/abci/client/local_client.go
index d4e8aecd7..a589fa02f 100644
--- a/abci/client/local_client.go
+++ b/abci/client/local_client.go
@@ -42,17 +42,6 @@ func (app *localClient) Error() error {
 	return nil
 }
 
-func (app *localClient) CheckTxAsync(ctx context.Context, req types.RequestCheckTx) (*ReqRes, error) {
-	app.mtx.Lock()
-	defer app.mtx.Unlock()
-
-	res := app.Application.CheckTx(req)
-	return app.callback(
-		types.ToRequestCheckTx(req),
-		types.ToResponseCheckTx(res),
-	), nil
-}
-
 //-------------------------------------------------------
 
 func (app *localClient) Flush(ctx context.Context) error {
@@ -213,16 +202,3 @@ func (app *localClient) FinalizeBlock(
 	res := app.Application.FinalizeBlock(req)
 	return &res, nil
 }
-
-//-------------------------------------------------------
-
-func (app *localClient) callback(req *types.Request, res *types.Response) *ReqRes {
-	return newLocalReqRes(req, res)
-}
-
-func newLocalReqRes(req *types.Request, res *types.Response) *ReqRes {
-	reqRes := NewReqRes(req)
-	reqRes.Response = res
-	reqRes.SetDone()
-	return reqRes
-}
diff --git a/abci/client/socket_client.go b/abci/client/socket_client.go
index 8b199e4d9..ed1e24111 100644
--- a/abci/client/socket_client.go
+++ b/abci/client/socket_client.go
@@ -206,12 +206,6 @@ func (cli *socketClient) didRecvResponse(res *types.Response) error {
 
 //----------------------------------------
 
-func (cli *socketClient) CheckTxAsync(ctx context.Context, req types.RequestCheckTx) (*ReqRes, error) {
-	return cli.queueRequestAsync(ctx, types.ToRequestCheckTx(req))
-}
-
-//----------------------------------------
-
 func (cli *socketClient) Flush(ctx context.Context) error {
 	reqRes, err := cli.queueRequest(ctx, types.ToRequestFlush(), true)
 	if err != nil {
@@ -423,19 +417,6 @@ func (cli *socketClient) queueRequest(ctx context.Context, req *types.Request, s
 	return reqres, nil
 }
 
-func (cli *socketClient) queueRequestAsync(
-	ctx context.Context,
-	req *types.Request,
-) (*ReqRes, error) {
-
-	reqres, err := cli.queueRequest(ctx, req, false)
-	if err != nil {
-		return nil, queueErr(err)
-	}
-
-	return reqres, cli.Error()
-}
-
 func (cli *socketClient) queueRequestAndFlush(
 	ctx context.Context,
 	req *types.Request,
diff --git a/internal/consensus/mempool_test.go b/internal/consensus/mempool_test.go
index 6d0d0d81b..7f846161e 100644
--- a/internal/consensus/mempool_test.go
+++ b/internal/consensus/mempool_test.go
@@ -204,8 +204,8 @@ func TestMempoolRmBadTx(t *testing.T) {
 		// Try to send the tx through the mempool.
 		// CheckTx should not err, but the app should return a bad abci code
 		// and the tx should get removed from the pool
-		err := assertMempool(t, cs.txNotifier).CheckTx(ctx, txBytes, func(r *abci.Response) {
-			if r.GetCheckTx().Code != code.CodeTypeBadNonce {
+		err := assertMempool(t, cs.txNotifier).CheckTx(ctx, txBytes, func(r *abci.ResponseCheckTx) {
+			if r.Code != code.CodeTypeBadNonce {
 				t.Errorf("expected checktx to return bad nonce, got %v", r)
 				return
 			}
diff --git a/internal/consensus/replay_stubs.go b/internal/consensus/replay_stubs.go
index fc0ec312f..08eed5d69 100644
--- a/internal/consensus/replay_stubs.go
+++ b/internal/consensus/replay_stubs.go
@@ -22,7 +22,7 @@ var _ mempool.Mempool = emptyMempool{}
 func (emptyMempool) Lock()     {}
 func (emptyMempool) Unlock()   {}
 func (emptyMempool) Size() int { return 0 }
-func (emptyMempool) CheckTx(_ context.Context, _ types.Tx, _ func(*abci.Response), _ mempool.TxInfo) error {
+func (emptyMempool) CheckTx(context.Context, types.Tx, func(*abci.ResponseCheckTx), mempool.TxInfo) error {
 	return nil
 }
 func (emptyMempool) RemoveTxByKey(txKey types.TxKey) error   { return nil }
diff --git a/internal/mempool/mempool.go b/internal/mempool/mempool.go
index f60ead160..21429721d 100644
--- a/internal/mempool/mempool.go
+++ b/internal/mempool/mempool.go
@@ -5,7 +5,6 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"reflect"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -205,11 +204,12 @@ func (txmp *TxMempool) TxsAvailable() <-chan struct{} {
 	return txmp.txsAvailable
 }
 
-// CheckTx executes the ABCI CheckTx method for a given transaction. It acquires
-// a read-lock attempts to execute the application's CheckTx ABCI method via
-// CheckTxAsync. We return an error if any of the following happen:
+// CheckTx executes the ABCI CheckTx method for a given transaction.
+// It acquires a read-lock and attempts to execute the application's
+// CheckTx ABCI method synchronously. We return an error if any of
+// the following happen:
 //
-// - The CheckTxAsync execution fails.
+// - The CheckTx execution fails.
 // - The transaction already exists in the cache and we've already received the
 //   transaction from the peer. Otherwise, if it solely exists in the cache, we
 //   return nil.
@@ -228,7 +228,7 @@ func (txmp *TxMempool) TxsAvailable() <-chan struct{} {
 func (txmp *TxMempool) CheckTx(
 	ctx context.Context,
 	tx types.Tx,
-	cb func(*abci.Response),
+	cb func(*abci.ResponseCheckTx),
 	txInfo TxInfo,
 ) error {
 	txmp.mtx.RLock()
@@ -261,31 +261,29 @@ func (txmp *TxMempool) CheckTx(
 		return types.ErrTxInCache
 	}
 
-	reqRes, err := txmp.proxyAppConn.CheckTxAsync(ctx, abci.RequestCheckTx{Tx: tx})
+	res, err := txmp.proxyAppConn.CheckTx(ctx, abci.RequestCheckTx{Tx: tx})
 	if err != nil {
 		txmp.cache.Remove(tx)
 		return err
 	}
 
-	reqRes.SetCallback(func(res *abci.Response) {
-		if txmp.recheckCursor != nil {
-			panic("recheck cursor is non-nil in CheckTx callback")
-		}
+	if txmp.recheckCursor != nil {
+		return errors.New("recheck cursor is non-nil")
+	}
 
-		wtx := &WrappedTx{
-			tx:        tx,
-			hash:      txHash,
-			timestamp: time.Now().UTC(),
-			height:    txmp.height,
-		}
+	wtx := &WrappedTx{
+		tx:        tx,
+		hash:      txHash,
+		timestamp: time.Now().UTC(),
+		height:    txmp.height,
+	}
 
-		txmp.defaultTxCallback(reqRes.Request, res)
-		txmp.initTxCallback(wtx, res, txInfo)
+	txmp.defaultTxCallback(tx, res)
+	txmp.initTxCallback(wtx, res, txInfo)
 
-		if cb != nil {
-			cb(res)
-		}
-	})
+	if cb != nil {
+		cb(res)
+	}
 
 	return nil
 }
@@ -491,25 +489,20 @@ func (txmp *TxMempool) Update(
 //
 // NOTE:
 // - An explicit lock is NOT required.
-func (txmp *TxMempool) initTxCallback(wtx *WrappedTx, res *abci.Response, txInfo TxInfo) {
-	checkTxRes, ok := res.Value.(*abci.Response_CheckTx)
-	if !ok {
-		return
-	}
-
+func (txmp *TxMempool) initTxCallback(wtx *WrappedTx, res *abci.ResponseCheckTx, txInfo TxInfo) {
 	var err error
 	if txmp.postCheck != nil {
-		err = txmp.postCheck(wtx.tx, checkTxRes.CheckTx)
+		err = txmp.postCheck(wtx.tx, res)
 	}
 
-	if err != nil || checkTxRes.CheckTx.Code != abci.CodeTypeOK {
+	if err != nil || res.Code != abci.CodeTypeOK {
 		// ignore bad transactions
 		txmp.logger.Info(
 			"rejected bad transaction",
 			"priority", wtx.priority,
 			"tx", fmt.Sprintf("%X", wtx.tx.Hash()),
 			"peer_id", txInfo.SenderNodeID,
-			"code", checkTxRes.CheckTx.Code,
+			"code", res.Code,
 			"post_check_err", err,
 		)
 
@@ -519,13 +512,13 @@ func (txmp *TxMempool) initTxCallback(wtx *WrappedTx, res *abci.Response, txInfo
 			txmp.cache.Remove(wtx.tx)
 		}
 		if err != nil {
-			checkTxRes.CheckTx.MempoolError = err.Error()
+			res.MempoolError = err.Error()
 		}
 		return
 	}
 
-	sender := checkTxRes.CheckTx.Sender
-	priority := checkTxRes.CheckTx.Priority
+	sender := res.Sender
+	priority := res.Priority
 
 	if len(sender) > 0 {
 		if wtx := txmp.txStore.GetTxBySender(sender); wtx != nil {
@@ -577,7 +570,7 @@ func (txmp *TxMempool) initTxCallback(wtx *WrappedTx, res *abci.Response, txInfo
 		}
 	}
 
-	wtx.gasWanted = checkTxRes.CheckTx.GasWanted
+	wtx.gasWanted = res.GasWanted
 	wtx.priority = priority
 	wtx.sender = sender
 	wtx.peers = map[uint16]struct{}{
@@ -598,28 +591,20 @@ func (txmp *TxMempool) initTxCallback(wtx *WrappedTx, res *abci.Response, txInfo
 	txmp.notifyTxsAvailable()
 }
 
-// defaultTxCallback is the CheckTx application callback used when a transaction
-// is being re-checked (if re-checking is enabled). The caller must hold a mempool
-// write-lock (via Lock()) and when executing Update(), if the mempool is non-empty
-// and Recheck is enabled, then all remaining transactions will be rechecked via
-// CheckTxAsync. The order transactions are rechecked must be the same as the
-// order in which this callback is called.
-func (txmp *TxMempool) defaultTxCallback(req *abci.Request, res *abci.Response) {
+// defaultTxCallback is the CheckTx application callback used when a
+// transaction is being re-checked (if re-checking is enabled). The
+// caller must hold a mempool write-lock (via Lock()) and when
+// executing Update(), if the mempool is non-empty and Recheck is
+// enabled, then all remaining transactions will be rechecked via
+// CheckTx. The order transactions are rechecked must be the same as
+// the order in which this callback is called.
+func (txmp *TxMempool) defaultTxCallback(tx types.Tx, res *abci.ResponseCheckTx) {
 	if txmp.recheckCursor == nil {
 		return
 	}
 
 	txmp.metrics.RecheckTimes.Add(1)
 
-	checkTxRes, ok := res.Value.(*abci.Response_CheckTx)
-	if !ok {
-		txmp.logger.Error("received incorrect type in mempool callback",
-			"expected", reflect.TypeOf(&abci.Response_CheckTx{}).Name(),
-			"got", reflect.TypeOf(res.Value).Name(),
-		)
-		return
-	}
-	tx := req.GetCheckTx().Tx
 	wtx := txmp.recheckCursor.Value.(*WrappedTx)
 
 	// Search through the remaining list of tx to recheck for a transaction that matches
@@ -635,7 +620,7 @@ func (txmp *TxMempool) defaultTxCallback(req *abci.Request, res *abci.Response)
 		txmp.logger.Error(
 			"re-CheckTx transaction mismatch",
 			"got", wtx.tx.Hash(),
-			"expected", types.Tx(tx).Key(),
+			"expected", tx.Key(),
 		)
 
 		if txmp.recheckCursor == txmp.recheckEnd {
@@ -656,18 +641,18 @@ func (txmp *TxMempool) defaultTxCallback(req *abci.Request, res *abci.Response)
 	if !txmp.txStore.IsTxRemoved(wtx.hash) {
 		var err error
 		if txmp.postCheck != nil {
-			err = txmp.postCheck(tx, checkTxRes.CheckTx)
+			err = txmp.postCheck(tx, res)
 		}
 
-		if checkTxRes.CheckTx.Code == abci.CodeTypeOK && err == nil {
-			wtx.priority = checkTxRes.CheckTx.Priority
+		if res.Code == abci.CodeTypeOK && err == nil {
+			wtx.priority = res.Priority
 		} else {
 			txmp.logger.Debug(
 				"existing transaction no longer valid; failed re-CheckTx callback",
 				"priority", wtx.priority,
 				"tx", fmt.Sprintf("%X", wtx.tx.Hash()),
 				"err", err,
-				"code", checkTxRes.CheckTx.Code,
+				"code", res.Code,
 			)
 
 			if wtx.gossipEl != txmp.recheckCursor {
@@ -697,7 +682,7 @@ func (txmp *TxMempool) defaultTxCallback(req *abci.Request, res *abci.Response)
 }
 
 // updateReCheckTxs updates the recheck cursors using the gossipIndex. For
-// each transaction, it executes CheckTxAsync. The global callback defined on
+// each transaction, it executes CheckTx. The global callback defined on
 // the proxyAppConn will be executed for each transaction after CheckTx is
 // executed.
 //
@@ -717,7 +702,7 @@ func (txmp *TxMempool) updateReCheckTxs(ctx context.Context) {
 		// Only execute CheckTx if the transaction is not marked as removed which
 		// could happen if the transaction was evicted.
 		if !txmp.txStore.IsTxRemoved(wtx.hash) {
-			res, err := txmp.proxyAppConn.CheckTxAsync(ctx, abci.RequestCheckTx{
+			res, err := txmp.proxyAppConn.CheckTx(ctx, abci.RequestCheckTx{
 				Tx:   wtx.tx,
 				Type: abci.CheckTxType_Recheck,
 			})
@@ -726,7 +711,7 @@ func (txmp *TxMempool) updateReCheckTxs(ctx context.Context) {
 				txmp.logger.Error("failed to execute CheckTx during rechecking", "err", err)
 				continue
 			}
-			txmp.defaultTxCallback(res.Request, res.Response)
+			txmp.defaultTxCallback(wtx.tx, res)
 		}
 	}
 
diff --git a/internal/mempool/mempool_test.go b/internal/mempool/mempool_test.go
index 21e3743ed..e2cf12e07 100644
--- a/internal/mempool/mempool_test.go
+++ b/internal/mempool/mempool_test.go
@@ -565,14 +565,12 @@ func TestTxMempool_CheckTxPostCheckError(t *testing.T) {
 			_, err := rng.Read(tx)
 			require.NoError(t, err)
 
-			callback := func(res *abci.Response) {
-				checkTxRes, ok := res.Value.(*abci.Response_CheckTx)
-				require.True(t, ok)
+			callback := func(res *abci.ResponseCheckTx) {
 				expectedErrString := ""
 				if testCase.err != nil {
 					expectedErrString = testCase.err.Error()
 				}
-				require.Equal(t, expectedErrString, checkTxRes.CheckTx.MempoolError)
+				require.Equal(t, expectedErrString, res.MempoolError)
 			}
 			require.NoError(t, txmp.CheckTx(ctx, tx, callback, TxInfo{SenderID: 0}))
 		})
diff --git a/internal/mempool/mock/mempool.go b/internal/mempool/mock/mempool.go
index 2b32a7ce6..e8782c914 100644
--- a/internal/mempool/mock/mempool.go
+++ b/internal/mempool/mock/mempool.go
@@ -17,7 +17,7 @@ var _ Mempool = Mempool{}
 func (Mempool) Lock()     {}
 func (Mempool) Unlock()   {}
 func (Mempool) Size() int { return 0 }
-func (Mempool) CheckTx(_ context.Context, _ types.Tx, _ func(*abci.Response), _ mempool.TxInfo) error {
+func (Mempool) CheckTx(context.Context, types.Tx, func(*abci.ResponseCheckTx), mempool.TxInfo) error {
 	return nil
 }
 func (Mempool) RemoveTxByKey(txKey types.TxKey) error   { return nil }
diff --git a/internal/mempool/types.go b/internal/mempool/types.go
index 05d4ba3e3..d78517372 100644
--- a/internal/mempool/types.go
+++ b/internal/mempool/types.go
@@ -30,7 +30,7 @@ const (
 type Mempool interface {
 	// CheckTx executes a new transaction against the application to determine
 	// its validity and whether it should be added to the mempool.
-	CheckTx(ctx context.Context, tx types.Tx, callback func(*abci.Response), txInfo TxInfo) error
+	CheckTx(ctx context.Context, tx types.Tx, callback func(*abci.ResponseCheckTx), txInfo TxInfo) error
 
 	// RemoveTxByKey removes a transaction, identified by its key,
 	// from the mempool.
diff --git a/internal/proxy/app_conn.go b/internal/proxy/app_conn.go
index bc67f554a..f30757f45 100644
--- a/internal/proxy/app_conn.go
+++ b/internal/proxy/app_conn.go
@@ -31,7 +31,6 @@ type AppConnConsensus interface {
 type AppConnMempool interface {
 	Error() error
 
-	CheckTxAsync(context.Context, types.RequestCheckTx) (*abciclient.ReqRes, error)
 	CheckTx(context.Context, types.RequestCheckTx) (*types.ResponseCheckTx, error)
 
 	Flush(context.Context) error
@@ -152,11 +151,6 @@ func (app *appConnMempool) Flush(ctx context.Context) error {
 	return app.appConn.Flush(ctx)
 }
 
-func (app *appConnMempool) CheckTxAsync(ctx context.Context, req types.RequestCheckTx) (*abciclient.ReqRes, error) {
-	defer addTimeSample(app.metrics.MethodTiming.With("method", "check_tx", "type", "async"))()
-	return app.appConn.CheckTxAsync(ctx, req)
-}
-
 func (app *appConnMempool) CheckTx(ctx context.Context, req types.RequestCheckTx) (*types.ResponseCheckTx, error) {
 	defer addTimeSample(app.metrics.MethodTiming.With("method", "check_tx", "type", "sync"))()
 	return app.appConn.CheckTx(ctx, req)
diff --git a/internal/rpc/core/mempool.go b/internal/rpc/core/mempool.go
index 325d293cb..61d36e93a 100644
--- a/internal/rpc/core/mempool.go
+++ b/internal/rpc/core/mempool.go
@@ -34,19 +34,18 @@ func (env *Environment) BroadcastTxAsync(ctx context.Context, tx types.Tx) (*cor
 // DeliverTx result.
 // More: https://docs.tendermint.com/master/rpc/#/Tx/broadcast_tx_sync
 func (env *Environment) BroadcastTxSync(ctx context.Context, tx types.Tx) (*coretypes.ResultBroadcastTx, error) {
-	resCh := make(chan *abci.Response, 1)
+	resCh := make(chan *abci.ResponseCheckTx, 1)
 	err := env.Mempool.CheckTx(
 		ctx,
 		tx,
-		func(res *abci.Response) { resCh <- res },
+		func(res *abci.ResponseCheckTx) { resCh <- res },
 		mempool.TxInfo{},
 	)
 	if err != nil {
 		return nil, err
 	}
 
-	res := <-resCh
-	r := res.GetCheckTx()
+	r := <-resCh
 
 	return &coretypes.ResultBroadcastTx{
 		Code:         r.Code,
@@ -61,18 +60,18 @@ func (env *Environment) BroadcastTxSync(ctx context.Context, tx types.Tx) (*core
 // BroadcastTxCommit returns with the responses from CheckTx and DeliverTx.
 // More: https://docs.tendermint.com/master/rpc/#/Tx/broadcast_tx_commit
 func (env *Environment) BroadcastTxCommit(ctx context.Context, tx types.Tx) (*coretypes.ResultBroadcastTxCommit, error) {
-	resCh := make(chan *abci.Response, 1)
+	resCh := make(chan *abci.ResponseCheckTx, 1)
 	err := env.Mempool.CheckTx(
 		ctx,
 		tx,
-		func(res *abci.Response) { resCh <- res },
+		func(res *abci.ResponseCheckTx) { resCh <- res },
 		mempool.TxInfo{},
 	)
 	if err != nil {
 		return nil, err
 	}
 
-	r := (<-resCh).GetCheckTx()
+	r := <-resCh
 	if r.Code != abci.CodeTypeOK {
 		return &coretypes.ResultBroadcastTxCommit{
 			CheckTx: *r,
diff --git a/rpc/client/rpc_test.go b/rpc/client/rpc_test.go
index 883716c19..fbdf257ed 100644
--- a/rpc/client/rpc_test.go
+++ b/rpc/client/rpc_test.go
@@ -594,7 +594,7 @@ func TestClientMethodCallsAdvanced(t *testing.T) {
 			_, _, tx := MakeTxKV()
 
 			txs[i] = tx
-			err := pool.CheckTx(ctx, tx, func(_ *abci.Response) { ch <- nil }, mempool.TxInfo{})
+			err := pool.CheckTx(ctx, tx, func(_ *abci.ResponseCheckTx) { ch <- nil }, mempool.TxInfo{})
 
 			require.NoError(t, err)
 		}
@@ -636,7 +636,7 @@ func TestClientMethodCallsAdvanced(t *testing.T) {
 
 		_, _, tx := MakeTxKV()
 
-		err := pool.CheckTx(ctx, tx, func(_ *abci.Response) { close(ch) }, mempool.TxInfo{})
+		err := pool.CheckTx(ctx, tx, func(_ *abci.ResponseCheckTx) { close(ch) }, mempool.TxInfo{})
 		require.NoError(t, err)
 
 		// wait for tx to arrive in mempoool.